# coding: utf-8
# Your code here!
n = int(input())

if n >= 30:
    print("Yes")
else:
    print("No") n = int(input()) n int(input()) int input() input if n >= 30:
    print("Yes")
else:
    print("No") n >= 30 n 30 print("Yes") print "Yes" print("No") print "No" n = int(input()) int(input()) n
# coding: utf-8
# Your code here!
n = int(input())

if n >= 30:
    print("Yes")
else:
    print("No")